Once you start to understand what motivates people to engage with your content - whether that's a video, a blog post or some other experience - you can begin to build vibrant communities of participation. And today, since almost everything we do involves technology, it's getting easier and easier to determine what those motivators are.

Don't forget that unexpectedness can also have more to do with showing that you are human. Being authentic. Not being afraid to show your vulnerable side. Whether it's a video, or real life, these moments demonstrate something in human nature that we can all relate to.

I believe that TED Youth and YouTube together have great potential -- to inspire youth to use these powerful platforms to change the world and tell great stories. Moreover, as a psychologist who studies how these simple and easily accessible online tools shape youth values, I thought he missed an opportunity to inspire the youth who were so eagerly listening to his speech.

Rebecca Black. Double rainbows. Nyan cat. Why do some videos made by ordinary people become internet sensations? And what do the videos we love say about who we are? YouTube's Kevin Allocca breaks it down in this nostalgic viral video tour.